Activities in the framework of GSICS CNES GPRC Report GSICS Annual Meeting 4-8th March 2013, Williamsburg, VA Activities in the framework of GSICS CNES GPRC Report Bertrand Fougnie, Denis Jouglet, Patrice Henry Sophie Lachérade, Eric Péquignot CNES-DCT/SI/MO + support from CNES-DCT/ME

Williamsburg, Virginia GSICS Annual Meeting 4-8th March 2013, Williamsburg, VA Marquis de Lafayette Williamsburg, Virginia

Summary 1/2 Cross-calibration over Desert CEOS-IVOS Working Group 4 : webmeeting’12 Libya-4 workshop : webmeeting’12 Cross-calibration LEO/GEO  dedicated talk on SEVIRI Synergic calibration  dedicated talk the PARASOL work on the Ocean Color Virtual Constellation SEVIRI : webmeeting’12  dedicated talk Calibration over Moon  dedicated talk Intensive acquisitions with Pleiades – An introduction to “POLO” : Pleiades Orbital Lunar Observations

Summary 2/2 Calibration over Rayleigh Scattering  dedicated talk Implementation for several sensors Development plan Starting the ATBD writing Implementation for GEO – SEVIRI results IASI cross-calibration  dedicated talks Overview of IASI-B performances  opening day Cross-calibration between IASI-A, AIRS, IASI-B, and CRIS SADE Database opening

Cross-Calibration over Desert Sites

CEOS-IVOS Working Group 4 CEOS decision to setup small WG … to draft a CEOS endorsable best practice “procedure” for the various vicarious cal/val methodologies WG4 on pseudo-invariant calibration sites (here Libya-4,Niger-2, Dome-C) The WG4 (intentionally restricted) Compare the results from 1/ selection and 2/ calibration Understand differences between methodologies Medium Resolution / Multi-spectral : VGT, MERIS, MODIS, PARASOL (4 years) DIMITRI (ESA), MUSCLE/SADE (CNES), DMA (RAL), OSCAR (VITO) Conclusion & lessons learnt a clear definition of reference datasets, protocol and outputs is required the extraction step (geographic + radiometric) is crucial for the performance general consistency between methods within 2-3% (after spectral correction) no significant bias between deserts BUT benefit to use different sites (snow/desert) possibility to extend the set in the future this exercise was beneficial for all methodologies (mistakes, limitations, improvements) GSICS WebMeeting Nov’12

CEOS-IVOS Libya-4 Workshop Focus technical exchange and experiences on one calibration site on of the most widely used – not the best geographical definition differs in general Participants mainly European, but also US (space agencies, labs, industries) Site characterization Spectral behavior : to be improved using Hyperspectral / spectral lab + Model BRDF: to be improved – CNES provide their current model for evaluation Atmosphere : statistical approach Improve surface of TOA characterization ? Intercalibration results if spectrally close channels : cross-calibration within 2-3% multi-date better than 2% for long-term trend absolute calibration : 5% (?) difficulty in the blue Paving the way for international collaboration and exchange GSICS WebMeeting Nov’12

Desert sites – What’s new ? ATBD – The IEEE TGARS Special Issue opportunity Bidirectional characterization of sites continuation of modeling using PARASOL data archive (bidirectional sensor) automatic procedure have been operated to generate BRDF models deep evaluation has to be done : made for Libya-4 (see WG) currently not fully satisfying… Prototyping of a new geometrical matching approach use of BRDF to enlarge the matching on a larger geometrical window Interest = largely increase the number of matchup when necessary to be fully validated and pushed on the operational phase Update of the MERIS archive – now Version 3 confirmation of the consistency with MODIS-Aqua within 1-2% Construction and analysis of a SeaWiFS archive behavior to be explained Cross-calibration LEO/GEO through SEVIRI data prototype phase – preliminary results under analysis very preliminary results shown at webmeeting Dec’12 Cross-calibration with MODIS not yet available, but very soon….

Synergic Calibration

What does it mean ? Several calibration methods are operational Statistical approach over natural targets Desert, Rayleigh, Sunglint, Cloud-DCC, Antarctica, Moon Each one has its own behavior : magnitude, spectral, angular, polarized… efficiency range Different aspects of calibration Indicative cartography – range of efficiency for each method

What does it mean ? See coming presentation 8d Basic idea = develop the synergic use of several method in order to : Take advantage of the complementarities of all method Document the confidence from consistency between methods Improve the “system calibration” when integrating various results Assess radiometric aspects others that the absolute calibration Recent example#1 : PARASOL end-of-life reCalibration Multi-method Synergic Approach to derive corrections of 1/ variation of calibration inside the field-of-view 2/ temporal evolution of the mean calibration 3/ reevaluate the absolute calibration for the entire archive Recent example#2 : Ocean Color Virtual Constellation Multi-sensor Synergic Approach to better understand and document 1/ the calibration and radiometric behavior of each sensor 2/ the consistency between calibration Recent example#2 : SEVIRI/MSG2 Multi-method Synergic Approach to the calibration from a GEO orbit See coming presentation 8d

Calibration over Moon

An introduction to “POLO” It has been demonstrated that the Moon is a very precious way to provide accurate in-orbit monitoring of the radiometric drift Activity under “big” development at CNES Method implemented in the operational MUSCLE/SADE environment Starting of Pleiades 1A and 1B commissioning phases in Jan’12 and Jan’13 Strong ability to “catch” the moon Intensive acquisitions have been performed (recom phase = 40°) 1 moon every day during one lunar cycle various moon cycles several moons during the day : every orbit, 2 successively, half an orbit 1 moon simultaneously by PH1A and PH1B This defines the Pleiades Orbital Lunar Observations – “POLO” Intensive in-orbit acquisitions in various conditions Goals are to better understand the ROLO model on its operational form to quantify the potential impact of programmation, conditions of acquisition (orientation), spatial sampling and resampling to derive recommendations to contribute to improve the use of lunar acquisitions to develop the use for cross-calibration See coming presentation 8h

Calibration over Rayleigh Scattering

Implementation Historically developed with POLDER and Végétation sensors definition, prototyping and improvements between 1998-2003 now stabilized on the reference Version 3.5 Implementation of Version 3.5 for several sensors ocean color sensor considered as radiometric reference SeaWiFS (prototype step) MERIS (operational, reprocessed for data V3) also to prepare OLCI (Sentinel-3) MODIS coming high-resolution sensors (limited geographical coverage and matchups) SPOT6 Pleiades 1A and 1B geostationary sensor SEVIRI future sensors Sentinel-2 Sentinel-3 (OLCI and SLSTR) VENUS SPOT7

Development Plan Why do we need to clarify a development plan Better visibility on the state of the art for each sensor Externally, but also internally The method is labeled “operational”, but method = step 1 = Data selection/extraction : specific step for each sensor (as if common baseline) step 2 = Algorithm : computation of TOA signal – universal step, but need LUT step 3 = matchup strategy : i.e. temporal/geometrical sampling : may be specific for each sensor = not the same development status for each sensor Development Plan for Calibration Method (MUSCLE/SADE) First tentative for the reference method Rayleigh Calibration Version 3.5 (GSICS inspired graphical representation) DEV = study & ATBD first definition [resp. SI/MO] PROTO = prototype on dedicated test environment on MUSCLE [resp. SI/MO] Final ATBD (data selection/extraction) computation of LUT, parameterization of SADE/MUSCLE Pre-OPE = test on the operational MUSCLE [resp. ME/EI] OPE = fully operational method/procedure/processing Traceability guaranteed [resp. ME/EI]

Development Plan The reference method is Rayleigh Calibration Version 3.5 DEV = study & ATBD first definition [resp. SI/MO] PROTO = prototype on dedicated test environment on MUSCLE – Final ATBD [resp. SI/MO] Pre-OPE = test on the operational MUSCLE [resp. ME/EI] OPE = fully operational method / Traceability guaranteed [resp. ME/EI]

Activities on Rayleigh Calibration Error budget : Continuity of efforts  see presentation 8a about Rayleigh cal. Construction of the error tree Construction of the error factors Results for SEVIRI  see presentation 4b about SEVIRI calibration prototyped in MUSCLE/SADE Rayleigh scattering results for synergic use  see presentation 8d validation of the temporal monitoring validation of the multi-angular calibration ocean color virtual constellation The GSICS-ATBD construction  see presentation 8a about Rayleigh cal. first outlines for LEO sensors See coming presentation 8a

IASI Cross-calibrations

IASI-B Performances IASI Commissioning Phase - Key dates MetOp-B launch: 17th Sept 2012 IASI first interferograms (start of L1 CalVal): 23th Oct 2012 IASI first L0 spectra (computed on-board): 24th Oct 2012 IASI first L1 spectra (calibrated on ground): 25th Oct 2012 Last configuration update before IASI-B L1C trial dissemination: On-board: 10th Jan 2013 Ground: 14th Jan 2013 IASI-B L1C trial dissemination (CalVal partners) in Near Real Time: 22th Jan 2013 IASI-B L1C trial dissemination (member states) in Near Real Time: 5th Feb 2013 See opening day’s presentation

IASI-B Performances See opening day’s presentation After 3 months of IASI-B L1 CalVal Instrument & interferogram acquisition are very stable and work perfectly Space & ground segments are now working well with consolidated parameters. The in-depth tuning has started. Performances are very encouraging and already of order of IASI-A

Massive Cross-calibration The tool for inter-comparison is now operational for the 5 couples of sensors: IASI-A / AIRS, IASI-A / CRIS IASI-B / AIRS, IASI-B / CRIS IASI-A / IASI-B Major result: very accurate cross-calibration! Bias between 0K and 0.2K, < radiometric absolute specification of 0.5K IASI-B very close to IASI-A (bias ~0.1K)  continuity of the IASI mission Work on-going: Increase the size and relevance of the dataset Go further in the interpretation of small differences Perform IASI / AIRS and IASI / CRIS at high spectral resolution Perform a spectral inter-calibration ? The tool should be operational for a long time (decades for climatic studies)  Inclusion of the future sensors (IASI-C, IASI-NG, etc.) See presentation 5a

SADE Database Opening

SADE Database Opening Few feedbacks from beta-users : only one (very positive…) SADE access through CNES scientific mission website http://smsc.cnes.fr/CALIBRATION/ (free access) Password mandatory (for the “SADE data” page only) A complete reprocessing of SADE exported files was produced in March 2012 Data extension up to 2011 New sensors : Terra/Modis Landsat 7 Theos New MERIS reprocessing (3rd) VGT1 updated calibration Opening has been announced at the CEOS/IVOS Meeting (May 2012) Nevertheless a small difficulty : no procedure yet available for password delivery (contact Aimé Meygret or Patrice Henry) including the data policy If interested, please contact us